From: Akeem G Abodunrin <akeem.g.abodunrin@intel.com> commit bc8a76a152c5f9ef3b48104154a65a68a8b76946 upstream. Intel ID: PSIRT-TA-201910-001 CVEID: CVE-2019-14615 Intel GPU Hardware prior to Gen11 does not clear EU state during a context switch. This can result in information leakage between contexts. For Gen8 and Gen9, hardware provides a mechanism for fast cleardown of the EU state, by issuing a PIPE_CONTROL with bit 27 set. We can use this in a context batch buffer to explicitly cleardown the state on every context switch. As this workaround is already in place for gen8, we can borrow the code verbatim for Gen9. Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@intel.com> Cc: Kumar Valsan Prathap <prathap.kumar.valsan@intel.com> Cc: Chris Wilson <chris.p.wilson@intel.com> Cc: Balestrieri Francesco <francesco.balestrieri@intel.com> Cc: Bloomfield Jon <jon.bloomfield@intel.com> Cc: Dutt Sudeep <sudeep.dutt@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/gpu/drm/i915/intel_lrc.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 6937ef0b..13e97fa 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1562,6 +1562,15 @@ static u32 *gen9_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch) /* WaFlushCoherentL3CacheLinesAtContextSwitch:skl,bxt,glk */ batch = gen8_emit_flush_coherentl3_wa(engine, batch); + /* WaClearSlmSpaceAtContextSwitch:skl,bxt,kbl,glk,cfl */ + batch = gen8_emit_pipe_control(batch, + PIPE_CONTROL_FLUSH_L3 | + PIPE_CONTROL_GLOBAL_GTT_IVB | + PIPE_CONTROL_CS_STALL | + PIPE_CONTROL_QW_WRITE, + i915_ggtt_offset(engine->scratch) + + 2 * CACHELINE_BYTES); + batch = emit_lri(batch, lri, ARRAY_SIZE(lri)); /* WaClearSlmSpaceAtContextSwitch:kbl */ -- 1.8.3